def test_read():
f = BlobIO(b'test' * 1000)
assert f.read(6) == b'testte'
assert f.tell() == 6
assert f.read(6) == b'sttest'
assert f.tell() == 12
def test_read_all():
f = BlobIO(b'test' * 3)
assert f.read() == b'testtesttest'
assert f.tell() == 12
assert f.read() == b''
f.seek(6)
assert f.read() == b'sttest'
def test_out_of_bounds_read():
f = BlobIO(b'test' * 1000)
f.seek(3998)
assert f.read(10) == b'st'
assert f.tell() == 4000
assert f.read(10) == b''
assert f.tell() == 4000
f.seek(5000)
assert f.read(10) == b''
def __init__(self, blob, verify_checksum=False):
pe_offs, = _read(blob[0x3c:], '<H')
fin = BlobIO(blob[pe_offs:])
sig = fin.read(4)
if sig != b'PE\0\0':
raise RuntimeError('Not a PE file: PE signature is missing.')
hdr = _IMAGE_FILE_HEADER.unpack_from_io(fin)
opt_sig, = struct.unpack('<H', fin.read(2))
if opt_sig == IMAGE_NT_OPTIONAL_HDR32_MAGIC:
opt = _IMAGE_OPTIONAL_HEADER32.unpack_from_io(fin)
opt.sig = opt_sig
elif opt_sig == IMAGE_NT_OPTIONAL_HDR64_MAGIC:
opt = _IMAGE_OPTIONAL_HEADER64.unpack_from_io(fin)
opt.sig = opt_sig
else:
raise RuntimeError('Unknown optional header type.')
self._checksum_offs = pe_offs + 4 + _IMAGE_FILE_HEADER.size + 4 * 16
if verify_checksum:
if opt.CheckSum == 0:
self.checksum_correct = False
else:
real_checksum = pe_checksum(
rope(blob[:self._checksum_offs], b'\0\0\0\0',
blob[self._checksum_offs + 4:]))
self.checksum_correct = real_checksum == opt.CheckSum
if opt.FileAlignment == 0:
raise RuntimeError(
'IMAGE_OPTIONAL_HEADER.FileAlignment must be nonzero')
dds = [
_IMAGE_DATA_DIRECTORY.unpack_from_io(fin)
for dd_idx in range(opt.NumberOfRvaAndSizes)
]
def make_pe_section(idx, hdr):
name = hdr.Name.rstrip(b'\0')
if hdr.PointerToRawData % opt.FileAlignment != 0:
raise RuntimeError('Section {}@{} is misaligned ({})'.format(
name, idx, hdr.PointerToRawData))
if hdr.SizeOfRawData % opt.FileAlignment != 0:
raise RuntimeError(
'Size of section {}@{} is misaligned ({})'.format(
name, idx, hdr.SizeOfRawData))
if hdr.PointerToRawData == 0:
data = None
else:
data = blob[hdr.PointerToRawData:hdr.PointerToRawData +
hdr.SizeOfRawData]
return _PeSection(hdr, data)
sections = [
make_pe_section(sec_idx, _IMAGE_SECTION_HEADER.unpack_from_io(fin))
for sec_idx in range(hdr.NumberOfSections)
]
present_secs = sorted(
(sec for sec in sections if sec.hdr.SizeOfRawData != 0),
key=lambda sec: sec.hdr.PointerToRawData)
if not present_secs:
raise RuntimeError('no present sections')
i = 1
while i < len(present_secs):
if present_secs[i - 1].hdr.PointerToRawData + present_secs[
i - 1].hdr.SizeOfRawData != present_secs[
i].hdr.PointerToRawData:
raise RuntimeError('there are holes between sections')
i += 1
last_sec = present_secs[-1]
end_of_image = last_sec.hdr.PointerToRawData + last_sec.hdr.SizeOfRawData
self._blob = blob
self._dos_stub = blob[:pe_offs]
self._file_header = hdr
self._opt_header = opt
self._data_directories = dds
self._sections = sections
self._trailer_offset = end_of_image
self._trailer = blob[end_of_image:]
self._check_vm_overlaps()